THE IMPACT OF TOTAL ENTERAL NUTRITION ON DISTRACTION OSTEOGENESIS IN A RAT MODEL

Limb lengthening by gradual mechanical distraction, termed distraction osteogenesis (DO), results in new bone formation. We have developed a rat tibial model for DO and have proceeded to study the effects of nu trition on this process. We have combined the intragastric diet delive ry system of total enteral nutrition (TEN) with DO in the rat model. T he first study was designed to address the weight loss associated with DO in dogs and patients. Rats in the chow + DO group lost 10% body we ight over the 20-day distraction period but gradually gained weight ba ck to the preoperative level by the end of the 5th week of the hone co nsolidation period, In contrast, in the TEN + DO group, a weight gain was recorded during the 20-day distraction phase. A second study was c onducted to determine the effects of TEN on the rate and histology of regenerate bone formation. The weight changes replicated those seen in the first study. Standardized radiographs, taken on day 20, revealed increases (p < 0.003) in regenerate bone formation in the TEN group wh en compared with the chow group. Increased numbers of osteoclasts in t he TEN group may indicate an accelerated entry into the remodeling pha se of consolidation. Serum IGF-I values, taken at day 20, did not diff er between the groups. These results demonstrate that the nutritional support dramatically increased the mineralized bone formed over the 20 -day distraction period.